Abstract : A low pass pi section digital phase shifter apparatus having an inductor and a diode connected in series between two identical parallel circuits. The parallel circuits connect to the series inductor/diode circuit at both the input and output and each circuit has inductor connected in parallel with a capacitor and a diode to provide balanced insertion loss at each diode switching state. When the diodes of the circuit are in the forward biased state they act as closed short circuit switches. When the diodes are reversed biased, the inductance in the series circuit resonates with the diode capacitance to provide a short circuit path to the RF signal to pass the center frequency of the RF signal at the desired phase.